The present invention relates to fabric-like webs of substantially randomly deposited continuous filaments of a thermoplastic polymer and, more particularly, to webs of this type which possess desirable elastic characteristics.
Nonwoven webs of substantially continuous and randomly deposited, molecularly oriented filaments of a thermoplastic polymer are widely known. Among others, the following patents illustrate a variety of methods for preparing such webs: Kinney (U.S. Pat. Nos. 3,338,992 and 3,341,394); Levy U.S. Pat. No. 3,276,944); Peterson (U.S. Pat. No. 3,502,538); Hartmann (U.S. Pat. Nos. 3,502,763and 3,509,009); Dobo et al. (U.S. Pat. No. 3,542,615); and Harmon (Canadian patent 803,714).
While many different methods are illustrated for initially preparing continuous filament webs, the available methods generally have at least three common features. First, the methods of preparation involve continuously extruding a thermoplastic polymer (either from the melt or a solution) through a spinneret in order to form discrete filaments. Thereafter, the filaments are drawn (either mechanically or pneumatically) in order to molecularly orient the polymer filaments and achieve tenacity. Lastly, the filaments are deposited in a substantially random manner onto a carrier belt or the like and thereafter usually bonded to yield a stabilized web with substantially isotropic physical characteristics.
The continuous filaments in webs prepared as described above are not normally elastic. As a result, webs containing the filaments are not usually considered to be elastic materials. The lack of elasticity tends to eliminate the use of these continuous filament webs in many end use applications, such as for certain garment materials, where elasticity is necessary.